Spinning wheels got to go round.
Spinning hand wheels for 3 days has actually got my biceps sore. Prepping a pair of molds for an injection molding product and the person who cut the core and cavity didn’t machine the outside of the mold with the same care as the inside. Consequently .020″ had to be removed from two cavities and two cores simultaneously, a 5-in thick block of steel when all assembled that has to be perfect so it has to be ground.
The grinder only removes about .0005″ per pass. The wheel is a half inch thick with .050 stepover each stroke. The feed is completely manual on this machine.
So cycle the table left to right, and back. This is just over a full revolution of the handwheel with the left hand. Then index over .050″.
Thats 100 cycles to remove .0005″.
I need to remove .020. So i have to repeat this 40 times.
That’s 4,000 repetitions. It’s not hard, the machine is doing the work. It’s repetetive and tedious.
And now i have to do the other three sides. So 16,000 repetitions.
But when i get done, they are perfect.
Then two pieces, the cavities, were left .250″ tall, so i have to run these on the bridgeport. Thank G-d it has power feed. Still, three passes ( since i don’t have a 5″ wide cutter and wouldnt want to swing one in a btidgeport anyway)at .010 each means 75 passes back and forth total, and did i mention the parts had to be fixtured perfectly flat? It took as long to set up each one as to cut it, and that was a half day per part.
The surface grinder is our “newest” tool, i believe it is from 1974. It is well made and was carefully kept.
The bridgeport i generally choose to use is apparently a 1956. It is clean and well kept, and i believe it was a special order since it has black dials instead of the (expected) chrome.
The fact that i am able to coax 50-70 year old machinery into doing this quality of work is impressive- but it’s all the machines, not me.
You can still buy machines of this quality, and some are even American made.
The men who made these machines, well, those are getting hard to come by. Oh, there are some. There are driven, hardworking people in each generation. But that’s not the money bet anymore.
Look for Tim Besmer on facebook. He’s got the Bridgeport group I started, and he rebuilds the things, also has sources for new, quality, gear…
“The fact that i am able to coax 50-70 year old machinery into doing this quality of work is impressive” – probably sums up what my boos will say about me in my performance review. :-)
Today I was on the phone a few times mentoring a young one through a differential rebuild.
I wasn’t sure why he wasn’t quite getting the detail I was laying down. “Look, this thing needs every bit as much or even more precision than building an engine. The forces you are playing with are mind-boggling. If you take the time to make it as perfect as you can it will last your lifetime. If you cut just one single corner it WILL grenade on a tow”.
He said that explained everything.
Reminds be of my younger years.
We no longer prize the ability to do things to fix things.
Hard times make hard men. Easy times make easy men, which bring on hard times.
I thing some really hard times are near.